Dataset Information

Vitamin D modulates biliary fibrosis in ABCB4-deficient mice.

ABSTRACT:

Purpose

Impaired vitamin D receptor signaling represents an aggravating factor during liver injury, and recent studies suggest that vitamin D might exert a protective role in chronic hepatobiliary diseases. We hypothesized that vitamin D supplementation would ameliorate liver fibrosis in ATP-binding cassette transporter B4 knockout (Abcb4 (-/-)) mice as a preclinical model of sclerosing cholangitis.

Methods

Abcb4 (-/-) and wild-type mice were fed a regular chow diet (600 IU vitamin D/kg food) or diets with lower (100 IU/kg) and higher (2,400 IU/kg) vitamin D concentrations for 12 weeks. Serum 25-hydroxyvitamin D concentrations were measured by chemiluminescence immunoassays. Liver injury and biliary fibrosis were assessed by liver enzyme activities, histopathology and hepatic collagen contents. Hepatic mRNA expression of markers for fibrosis, vitamin D and bile acid metabolism were analyzed by quantitative PCR.

Results

Different vitamin D concentrations were observed depending on genotype and diet group, with Abcb4 (-/-) mice on the control diet showing lower vitamin D concentrations compared to wild-type mice. Abcb4 (-/-) animals on the low vitamin D diet demonstrated the most advanced liver fibrosis and highest hepatic collagen contents. Feeding Abcb4 (-/-) mice a high vitamin D diet enriched serum vitamin D levels, lowered liver enzyme activities, altered expression levels of profibrogenic genes and ameliorated, in part, liver injury.

Conclusions

This is the first report to demonstrate that fibrogenesis in the established Abcb4 (-/-) model is influenced by vitamin D supplementation. Since vitamin D modulates sclerosing cholangitis in vivo, we speculate that sufficient vitamin D intake might improve liver damage and induce antifibrotic effects in chronic cholestasis in humans.

SUBMITTER: Hochrath K

PROVIDER: S-EPMC4148166 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Publications

Vitamin D modulates biliary fibrosis in ABCB4-deficient mice.

Hochrath Katrin K Stokes Caroline S CS Geisel Jürgen J Pollheimer Marion J MJ Fickert Peter P Dooley Steven S Lammert Frank F

Hepatology international 20140621 3

<h4>Purpose</h4>Impaired vitamin D receptor signaling represents an aggravating factor during liver injury, and recent studies suggest that vitamin D might exert a protective role in chronic hepatobiliary diseases. We hypothesized that vitamin D supplementation would ameliorate liver fibrosis in ATP-binding cassette transporter B4 knockout (Abcb4 (-/-)) mice as a preclinical model of sclerosing cholangitis.<h4>Methods</h4>Abcb4 (-/-) and wild-type mice were fed a regular chow diet (600 IU vitami ...[more]

PMID: 25191532

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Project description:Background and Aims - Bile acids (BAs) aid intestinal fat absorption and exert systemic actions by receptor-mediated signaling. BA receptors have been identified as drug targets for human diseases, but differences in BA metabolism between humans and mice hamper translation of pre-clinical outcomes. Cyp2c70-ablation in mice prevents synthesis of mouse/rat-specific muricholic acids (MCAs), but potential (patho)physiological consequences of their absence are unknown. We therefore assessed age- and gender-dependent effects of Cyp2c70-deficiency in mice. Methods - BA-related parameters, hepatic and intestinal gene expression patterns, liver morphology and intestinal barrier function were assessed in male and female Cyp2c70-/- mice and WT controls at different ages. Effects of ursodeoxycholic acid (UDCA) treatment were evaluated in young adult female mice. Results – Cyp2c70-/- mice were completely devoid of MCAs and showed high abundances of chenodeoxycholic and lithocholic acids. BA pool size was unaffected in young-adult male but reduced by 40% in female Cyp2c70-/- mice. Interestingly, plasma BAs and transaminases were highest in Cyp2c70-/- mice at weaning and spontaneously decreased with age. Although bile flow and biliary BA secretion were unchanged in young-adult Cyp2c70-/- mice, indicating absence of cholestasis, plasma BA and transaminase levels were still elevated. These young-adult Cyp2c70-/- mice displayed cholangiocyte proliferation, mild portal fibrosis, altered microbiome composition and increased gut permeability. Only the female Cyp2c70-/- mice developed bridging fibrosis with age (7-8 months). UDCA treatment normalized hepatic and intestinal functions and fully restored liver morphology in female Cyp2c70-/- mice. Conclusion – Cyp2c70-/- mice show transient neonatal cholestasis and develop cholangiopathic features which progress to bridging fibrosis in female mice only. These consequences of Cyp2c70-deficiency are fully restored by treatment with UDCA.

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Dataset Information

Vitamin D modulates biliary fibrosis in ABCB4-deficient mice.

Purpose

Methods

Results

Conclusions

Publications

Vitamin D modulates biliary fibrosis in ABCB4-deficient mice.

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